It all started when Piers shared an article from The Sun on Twitter with the headline: "Beverley Callard says celebs are trying to make mental health problems 'fashionable'."

Photo credit: ITV

In sharing the link, Piers added: "She'll be hammered for saying this, but it's 100% true."

Speaking about her own experiences with mental illness, Callard had told Best Magazine: "Real mental illness is very dark and it takes a great deal of strength to ask for help.

“I think we are now definitely chipping away at the stigma. But we have to be careful mental illness doesn’t become like a Gucci handbag. There is a danger it can become ‘fashionable’.”

But Piers' tweet didn't go down very well with Game of Thrones star Sophie Turner, who replied: "Or maybe they have a platform to speak out about it and help get rid of the stigma of mental illness which affects 1 in 4 people in UK per year.

"But please go ahead and shun them back into silence. Twat."

Or maybe they have a platform to speak out about it and help get rid of the stigma of mental illness which affects 1 in 4 people in UK per year. But please go ahead and shun them back into silence. Twat. https://t.co/mvddYPjcht

Never one to back down, Piers then responded: "Hi Sophie, please don't abuse me like this - it's harmful to my mental health. Thanks."

He went on to say: "Why would I listen to yet another woefully unqualified C-list celebrity lecturing me about mental health to make herself look good, grab a few laughable 'She DESTROYED Piers Morgan!!' headlines & get lots of 'likes'? Just virtue-signalling nonsense."

Why would I listen to yet another woefully unqualified C-list celebrity lecturing me about mental health to make herself look good, grab a few laughable ‘She DESTROYED Piers Morgan!!’ headlines & get lots of ‘likes’? Just virtue-signalling nonsense. https://t.co/QL04GQqND0

Sophie's yet to respond to Piers specifically (although he better be careful, as she recently told Digital Spy that she's now the "true leader of Winterfell"), but she did post a series of inspiring tweets about depression and mental health.

Part 1 : People who think it’s okay to make jokes about mental illness, I feel you must be lucky, because surely you don’t understand or can’t comprehend what it is like to have or know someone with an illness like this.

Speaking to those who are going through a tough time, Sophie wrote: "You are not alone, you can manage your illness, and people who make fun of it are the minority... not you. You are loved and supported."